1. Field of the Invention
The subject invention pertains to the art of glass grinding, and is particularly suited for beveling the edges of a square glass workpiece such as a mirror.
2. Description of the Prior Art
A variety of glass beveling machines is known in the art. Some glass beveling machines include a series of grinders and a series of polishers positioned along a single conveyor such that a single edge of the workpiece can be ground and polished in one pass through the device. More efficient prior art machines provide two sets of grinders and polishers disposed on either side of the conveyor such that two opposite parallel edges can be ground and polished in a single pass through the device.
In prior art systems, it is necessary to reposition the workpiece manually. Of course proper alignment of the workpiece for the grinding and polishing operations is essential. Failure to align a workpiece properly will cause it to jam, and probably shatter. Succeeding workpieces are also likely to jam and break until the conveyor can be cleared, leading to substantial reductions in yield. Because of variations in the amount of time necessary to accomplish this repositioning, substantial time intervals (i.e. substantial space on the moving conveyor) have to be allowed between successive workpieces in order to avoid the interference which will result if one workpiece cannot be satisfactorily repositioned before the succeeding workpiece arrives at the work station in question. Thus, prior art systems require excessive gaps between successive workpieces and suffer from a commensurate reduction in output capacity for a given apparatus.